1. Field of the Invention
The present invention relates generally to valve structures and more particularly to valve structures located in the hand-held portion of an oral evacuator system used in dental procedures.
2. Background Art
Oral evacuator systems are used in dental procedures to facilitate the removal of fluids and debris from the mouth of dental patients. Such evacuator systems include a hand-held portion which is connected to a vacuum source/waste disposal unit by way of a flexible hose. The hand-held portion includes a valve structure which may be actuated by either the patient or the dentist.
U.S. Pat. No. 4,015,336 issued to the present applicant discloses an exemplary prior art valve structure for use in an oral evacuator system. The valve structure includes an elongated housing having an external manually-actuated latch for opening and closing the valve. A slot is provided in the side of the housing to permit passage of a connecting element between the latch and a spring-biased poppet disposed within the housing.
One of the primary disadvantages of such prior art valve structures is that fluid and debris tend to escape through the access slot in the housing when the valve is closed. Such leakage is largely attributable to the fact that the access slot is positioned upstream of the valve. Thus, when the valve is closed, matter entrapped upstream of the valve can escape through the slot. Such prior art valve structures are also somewhat difficult to actuate, especially by persons having arithritic conditions and the like.
U.S. Pat. No. 4,081,176, also to applicant, discloses a valve structure which overcomes some of the disadvantages of the previously-described device. This structure avoids the use of openings in the housing with activation of the normally-closed valve being accomplished by manually extending a resilient element. However, in order to maintain the valve in an open position, it is necessary to maintain a constant force on the resilient element which can be quite tiring.
The present invention overcomes the above-noted disadvantages of the prior art. The valve structure disclosed herein has no tendency to leak and the valve may be easily activated and maintained in an open or closed position. These and other advantages of the present invention will become apparent to those skilled in the art upon reading the following detailed description of the invention together with the drawings.